1. Field of the Invention
The present invention relates to a hoisting frame, specifically for hoisting containers, that includes a longitudinally adjustable beam having a plurality of outer pickup elements arranged at its ends and inner pickup elements arranged near its center.
2. Description of the Prior Art
Such a hoisting frame is generally known, and may be used for hoisting two containers placed with their end faces adjacent one another. A problem which occurs here is that the positioning of the two containers adjacent one another is not always constant, and that therefore the spacing of the containers often varies. Thus in practice it is often not possible to pick up two containers at the same time with a single hoisting frame, so that it is then necessary to shorten the hoisting frame again for subsequently picking up the containers individually. This of course leads to a serious loss of time.
This problem occurs especially when transferring containers between shore and ship. Onshore containers will usually be stacked with a virtually constant spacing of no more than approximately 80 millimeters, whereas the stacking of containers on a ship depends on the specific structure of the ship, and will therefore vary from ship to ship. This is due to the requirement that the containers on a ship should be well stowed. This has for its result that during loading or unloading a container ship, it is often impossible to handle two containers at the same time, so that such loading or unloading takes a relatively much long time.
The invention therefore aims to provide a hoisting frame with which the above-mentioned drawbacks are obviated.